Slot insulating cell



Dec. 1a, 1928. 1,695,862

M. SANDFIELD SLOT INSULATING CELL Filed Sept. 16, 1926 Fig. 2.

I I I l I i i i i l l I 1 l I i l I i i i l I WITNESSES! INVENTOR fi, w. Michael Sand/laid ATITORNEY Patented Dec. 18, 1928.

UNITED STATES PATENT orries...

menial: sammmn, or rmsmmen, PENNSYLVANIA, ASSIGNOB "rownsrmm noose annc'rarc a MANUFACTURING COMPANY, A oonroanrron or mum- VANIA.

' snormsvnnrme CELL.

Application ahra umber 16,1926. Serial No. 135,889.

My invention relates to insulating structures and it has particular relation to the slot lining cells for the slotted: coresof dynamo-electric machines.

An object of. my invention is to provide a slot cell of 'mproved characteristics for partially closed slots. 1 I

The cell is so designed as to have a reenforcing bend or fold at each endfor preventing tearing of. the corners. of the slot cell when the conductor wires are pressed into lace. At the same time, the re-enforcing olds are so desi ed, that they do not cause the insulatingc ls to bulge out, but on the contrary, draw them into snug engagement with the sides of the conductors.

My censta'nctionis also such that perforations, and therefore leakage paths, in the insulation, are avoided, in contradistinction to certain 'giacticesof the prior art wherein a tape or inderhas been sewed over each end of the slot cell and wherein the needle holes have very much weakened the insulating qualities of the surface leakage path between the coils and the frame of themachine.

My invention will best be understood by reference to the accompanying drawing, wherein I Figure 1 is an end elevation of a partially assembled stator member of a dynamo-electric machine embodying my invention;

Fig. 2 is a longitudinal sectional view of the same, with the windings removed;

Fig. 3 is a plan view of the blank from which an insulating cell is formed; and

Figs. 4, 5 and 6 are plan, end and crosssectional views of a completed slot lining cell.

The problems and methods of winding partially closed-slot machines are described and illustrated in my article on Winding induction motors which appeared in the Electric Journal for December, 1923. With a general reference to thisarticle for a more detailed description of the general features of the art of winding dynamo-electric machines, I shall confine my present description to the novel features of my slot insulatin cell per se.

In 1g. 1, my invention is shown as applied to a stator member 7 having partial closed slots 8 which are provided with narrow openings 9, whereby thewires of the pre viously formed coils 10 may be individually pushed into the slots.

Before the coils are placed in the slots, the latter are lined withslotlining cells llvwhiclr are accurately shaped to lit the slotsandv areof suitable insulating materials,made prefer ably of a combination of treated-cloth and fish paper cementedtogcthcr, thetcloth supplying the insulating qualities, while the fish, paper furnishes the desired mechanical strength. When the coils 10 have all been inserted in place and the individual turnsof the coils are pressed. into position,it occasionally happens that the slot liningcells will tear at the bottom corners, sincee the cells must extend beyond the ends of. the core mem her, as indicated at 12in Fig. 2, in order toprovide a suitable insulating leakage path between the coils and the frame of the machine. I i I A most effective method of overcoming the tearing just mentioned, without entailing a bulky construction and without necessitating the perforation of the material of the lining cell, as by sewing, is to provide inturned flaps or folds 13 at the ends of each slot, the bends being arranged to be widest at the bottom of the cell and tapering off along the side edges of the cell.

I In Fig. 3, I have shown a blank 14 from which one of my slot lining cells 11 is made.

' The blank is of rectangular shape and is pro-- vided with two longitudinal bends 15 to form the bottom of the slot, as indicated by dotted lines in Fig.3. The end flaps 13 are formed I by providing inclined bends 16 in the ends of the side walls of the cell and a transverse cated in Fig. 3. In practice, the cell lining 7 material may be cut into shape and bent along the dotted lines 15, 16' and 17, all in 90 bend'17 in the bottom wall, as is clearly indi- I Q as Jcrinittcd by the standardization rules oi the American Institute of Electrical Engineers, resulting from the fact that the laminations are tightly squeezed together at points removed from the slotted periphery, as indicated by the bolt 20. It will be noted that the inclination of the end 0i i y folded slot cell is in the proper direction to correspond to the outward flare of the core laminations 19.

In the form of construction shown in the drawing, the cell 11 has lips 22 which insulate the wires from the slot-closing wedge 23 in the top of the slot.

A y invention is. however, obviously applicable to either a lippe-a cell or one having no lips the top of the slot. 7

I claim as my invention:

1. A slot cell comprising a rectangular sheet of insulating material having two longitudinal bends forming the bottom of. the

cell and having end bends forming inwardly bent flaps which are wider at the bottom than at the tops.

2. The combination with a dynamoclcctrio machine comprising a slotted core member, 01'' a slot cell comprising insulating bot tom and side walls extending beyond the ends of each oi. the slots, the ends of each slot cell being inturned to provide an overlapping flap which is smallest near the tops of the side walls and largest at the bottom wall of the cell, and a winding disposed in said slot cells.

3. The combination with a dynamo-electric machine comprising a core member harine" par rally closed slots, of a slot cell com prising insulating bottom and side walls for each slot and a winding disposed in said slot cells each slot cell having continuous, unperlo tcd extensions projecting beyond the ends 0? the core member and having inwardly bent flaps of such configuration as to cause the same to cling closely to the sides of the conductors lying in the slot.

in testimony whereof, I have hereunto subscibed my name this 8th day of September,

MICHAEL SANDFIELD.

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